Skin pack as well as method and sealing station for manufacturing a skin pack

ABSTRACT

A packaging known as a skin pack comprising a base and a top film surrounding a product. The top film may be a skin film and the base and the top film may be sealed together in a gas-tight manner along a circumferential sealing region. The base and the top film may extend in one or more edge regions outside the sealing region. In one embodiment, this extension creates an area of overlap outside the sealing region wherein the top film and the base are not sealed together, which may form a tear-open corner. The base may have a deformation or may be formed along an edge or at a corner so as to facilitate gripping the top film by a user.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims priority to European Patent Application No. 18 177 051.2 filed on Jun. 11, 2018 to Stefan Löffler and Harald Gehrke, currently pending, the entire disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention refers to a skin pack with a tear-open corner and to a method and a sealing station for manufacturing such a skin pack.

BACKGROUND OF THE INVENTION

Vacuum packaging, packaging in which air inside of the package is largely exhausted, is often used to pack food products in order to extend their shelf life. A further development is the so-called skin pack, in which an elastic top film, the skin film, is placed tension-free and close fitting over a base and a product positioned thereon. The base can also be in the form of a tray into which the product is inserted. The base and the top film are gas-tightly connected to each other after the packaging process, the sealing in a circumferential sealing region. The skin pack has properties which allow a particularly advantageous product presentation. This fixes the product positioned in the tray and prevents the product from falling apart or liquid from escaping from the product into the tray space. Due to the stable connection of base and top film in the sealing region, the product is securely fixed during transport and unintentional automatic opening of the skin pack is prevented. However, the firm connection between the base and the top film also makes it difficult for a consumer to open the pack in order to remove the product.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide an improved opening option for a skin pack.

A skin pack according to the invention comprises a base and a top film, wherein the top film is a skin film and wherein the base and the top film are gas-tightly sealed together along a circumferential sealing region. The base and the top film extend in one or more edge regions outside the sealing region, in particular in the form of a tear-open corner, and are not sealed together there. If the sealing region were to extend to the outermost edge of the skin pack, i.e. to the cutting edge thereof, it would be difficult for the consumer to detach the top film from the base in a small section, grasp the top film and remove it from the base in order to open the pack. If, however, the top film and the base are only laid loosely on top of each other in an edge section adjacent to the sealing region, the consumer can easily grasp the top film and pull it off from the base. Therefore, the consumer does not have to use any additional tools.

In an advantageous embodiment, the sealing region may comprise a sealing seam. The sealing seam may also be a circumferential region, usually relatively narrow and running in the edge region. In addition to the skin process explained below, the top film and the base may be connected to each other with pressure and heat in a particularly stable way. The sealing seam may be even stronger than the rest of the sealing region, which reliably prevents unintentional opening of the skin pack, even if particularly heavy or large products are packed or the packaging is subjected to particularly high mechanical loads during transport and sale.

In a particularly advantageous embodiment, the base may be provided in the edge region with an offset which the top film spans to facilitate gripping of the top film and thus opening of the skin pack by pulling off the top film. The offset, which can take the form, for example, of a step directed downwards or an inclination, allows the top film to be gripped directly without first having to be spread apart from the base by bending the edge of the pack or counter-pressing it. The offset may also be in the form of an upwardly directed knob or web, so that the top film is pressed upwards in the unsealed edge region and protrudes. All variants make it particularly easy to open the skin pack.

The base may be preferably designed as a tray, in particular as a thermoformed bottom film. A tray offers advantages when inserting the product, e.g. it prevents liquids from running off, and offers additional protection of the product through the lateral edges also when the package is closed. This also provides greater torsional stiffness than in the case of flat bases.

In another embodiment, the sealing region adjacent to the tear-open corner has a discrete angulation. If the top film is pulled from the tear-open corner onto the angulation or onto a corner of the sealing region, the force is concentrated particularly advantageously at one point on the corner or angulation and then distributed evenly on both sides of the angulation. This makes the top film particularly easy to pull off, especially if top film and base are joined by a sealing seam.

A sealing station according to the invention for manufacturing a skin pack may comprise a sealing tool upper part with a first frame and a concave dome comprising air channels, and a sealing tool lower part with a second frame and a base holder. The sealing tool upper part and/or the sealing tool lower part may be height-adjustably mounted in order to be brought closer to each other and to contact each other on their first and second frames, thus forming a gas-tight sealing tool chamber. The sealing station may also be configured to connect a base to a top film, which is a skin film, in a gas-tight manner by forming a sealing region. The first frame of the sealing tool upper part and the second frame of the sealing tool lower part may be configured to clamp a section of the base and a section of the top film so that they are excluded from heating and deformation during the sealing process. In this way, the necessary pressures and temperatures required for the sealing process, i.e. the connection of the top film to the base, can be created within the sealing tool chamber. At the same time, the clamped sections of top film and base may not be affected, which prevents the formation of a sealing region, i.e. a connection between top film and base, at that place. The sections can also extend further outwards and protrude beyond the frames, so that no sealing process takes place there either.

The sealing station may preferably comprise a height-adjustable sealing plate, wherein the sealing plate has a sealing surface which is suitable for connecting a base to a top film in a gas-tight manner by forming a sealing seam. The movable sealing plate presses the sealing surface onto the top film and the base, whereby these are supported on a bearing surface so that the desired contact pressure can be applied. This creates a particularly stable connection between the top film and the base. In addition, the sealing surface can be heated to additionally support the formation of the sealing seam.

The first frame of the sealing tool upper part and the second frame of the sealing tool lower part may be made of a material approved for the food industry. The same applies to the dome and the sealing plate in the sealing tool upper part. It may make sense that the material(s) from which the first frame and the second frame are made have a lower thermal conductivity than the material of the dome and the sealing plate in order to enable energy-efficient heating of the dome and sealing plate, but to minimize heat transfer to the frames. For example, in one embodiment, the frames could be made of stainless steel and the dome and sealing plate could be made of aluminum.

In another embodiment, the first frame of the sealing tool upper part and/or the second frame of the sealing tool lower part may be formed at least in sections from a plastic and/or ceramic material. For example, the sections which clamp the top film may have a particularly low thermal conductivity, which means that no heat is transferred to the top film. The use of such materials may be particularly useful in the area of the tear-open corner, for example to prevent heat from being transferred from the heated dome or sealing surface to the top film and the base.

In a common variant, the first frame of the sealing tool upper part and/or the second frame of the sealing tool lower part may be cooled, in particular water-cooled by channels running therein. In this way, unwanted heat transferred into the frames can also be dissipated. This is not only helpful for forming the unsealed opening aid or tear-open corner but also protects an operator of the sealing station or packaging machine from heat-related injuries when touching the frames.

The frame of the sealing tool lower part may include a recess that is designed to accommodate a downwardly projecting offset of the base in order not to deform the offset when clamping the base and the top film between the two frames. Accordingly, the frame of the sealing tool upper part may also have a recess to accommodate an offset projecting upwards from the flat base surface of the bottom film. The offset, which may create a distance between base and top film in order to be able to grip the latter in an improved way, is thus inserted into the recess and thereby retains its shape and thus its function even when the frames are pressed together.

Preferably, the sealing tool lower part may be at least partially replaceable in order to accommodate bases of different shapes, especially bases in tray form. In this way, the same sealing station may seal different packs as required. One way to achieve this may be the use of appropriate inserts which are inserted into the sealing tool lower part. The bases may then be placed in or on these inserts.

Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures.

DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the following, an advantageous embodiment of the present invention will be explained in more detail making reference to a drawing, in which the individual figures show:

FIG. 1A is a schematic lateral sectional view of one embodiment of a skin pack in accordance with the present disclosure showing a skin pack including a product and a flat base with a downwardly oriented offset in the form of a step;

FIG. 1B is a schematic lateral sectional view of one embodiment of a skin pack in accordance with the present disclosure showing a skin pack including a product and a flat base with a downwardly oriented offset in the form of an inclination;

FIG. 1C is a schematic lateral sectional view of one embodiment of a skin pack in accordance with the present disclosure showing a skin pack including a product and a flat base with an upwardly oriented offset in the form of a knob;

FIG. 2 is a schematic lateral sectional view of one embodiment of a skin pack in accordance with the present disclosure showing a skin pack including a product and a base in tray form;

FIG. 3 is an exploded perspective side view of one embodiment of a sealing station in accordance with the present disclosure showing a sealing tool upper part, a sealing tool lower part, and as four bases arranged in a group;

FIG. 4 is a bottom view of one embodiment of a sealing tool upper part in accordance with the teachings of the present disclosure;

FIG. 5 is a bottom perspective view of another embodiment of a sealing tool upper part in accordance with the teachings of the present disclosure; and

FIG. 6 is a schematic side sectional view of one embodiment of a sealing station in accordance with the teachings of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purposes of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures.

The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled.

FIG. 1A shows a sectional view of a skin pack 1 with an essentially flat base 3, on which a product 5 is placed and sealed with a top film 7, which is a skin film. In a circumferential sealing region 9, the base 3 and the top film 7 are sealed together in a gas-tight manner. An unsealed edge region 11 is formed on the left side of the skin pack 1, on which the base 3 and the top film 7 are not sealed together. In addition, an optional offset 13 in the form of a step is formed in the base 3, so that base 3 and top film 7 are spaced apart and the top film 7 can thus be gripped more easily in order to pull it off from the base 3 to open the skin pack 1.

FIG. 1B corresponds to the skin pack 1 as shown in FIG. 1A, but the offset 13 is in the form of an inclination.

FIG. 1C shows another variant of the skin pack 1 in which the offset 13 is formed as an upstanding knob. As shown, the knob can be pointed. In the same way, the knob can also be a substantially round and/or hollow, upwardly pressed, punctiform section of the base 3. However, it can also be a web with a certain longitudinal expansion in the base 3 in the unsealed edge region 11.

FIG. 2 shows a sectional view of a skin pack 1 with a base 3 in tray form. The skin film 7 surrounds the product 5 inserted into the tray 3, fixes it and lies against the inside of the tray 3 without play. The tray 3 has a raised circumferential and horizontal edge 15, on which the top film 7 with the base 3 forms a circumferential sealing region 9 and edge regions 11 that are unsealed in sections follow. One or more offsets 13 in the unsealed edge regions 11 can also be optionally formed.

FIG. 3 shows a perspective side view of a sealing station 17, comprising a sealing tool upper part 19 and a sealing tool lower part 21. The sealing tool upper part 19 comprises a first frame 23 and the sealing tool lower part 21 the second frame 25. For the sake of clarity, components for raising and lowering the first frame 23 and/or the second frame 25 or the components of the conveying section are not shown. The frames 23, 25 are designed to seal four skin packs 1 per work cycle. For this purpose, the four, usually interconnected, bases 3, here in the form of trays, are inserted into the second frame 25. In this case, base holders 27 for the trays 3 themselves as well as recesses 29 for the offsets 13 are formed in the second frame 25. The unsealed edge regions 11 in the form of tear-open corners are conveniently oriented towards the edges parallel to the transport direction T, i.e. towards transport chains guiding the top film 7, for example. The figure shows the circumferential sealing region 9 and the unsealed edge region 11 in the form of a tear-open corner with reference to the base 3. At the tear-open corners 11, the sealing region 9 has a discrete angulation 31, which improves the opening behavior when the top film 7 is pulled off.

On the side, holes 33 are arranged in the second, lower frame 25, which serve to evacuate the skin pack 1.

FIG. 4 shows the sealing tool upper part 19 from below. Inside the first frame 23 there are four domes 35 concavely curved upwards. The space between dome 35 and top film 7 can be evacuated via air channels 37 in the domes 35, so that the top film 7 rests on the respective dome 35 and can be heated by it. The first frame 23 has the appropriate shape to create the sealing region 9 in the region within the first and second frames 23, 25 as shown in FIG. 3 and the unsealed edge region 11 of the skin pack 1 adjacent to it. Furthermore, recesses 39 are formed in the first frame 23 in order to allow evacuation of the region between top film 7 and base 3, i.e. the interior of the skin pack 1, by using the holes 33.

FIG. 5 shows a perspective sectional view from obliquely below onto a sealing tool upper part 19. The first frame 23 has the shape which defines the sealing region 9 and the unsealed region 11 of the skin pack 1 (see FIG. 3). The two domes 35 in this embodiment are formed as part of a sealing plate 41. The sealing plate 41 is arranged to be movable relative to the first frame 23. This allows the sealing plate 41 to be moved downwards with the sealing tool chamber already closed and a sealing surface 43 to be pressed onto the top film 7 and the base 3 in order to connect them together in a particularly stable manner. An edge support of the sealing tool lower part 21, on which the corresponding sections of the top film 7 and the base 3 rest, creates the necessary counter pressure. The recesses 39 allow the evacuation of the skin pack 1 by using the holes 33 arranged in the second frame 25.

FIG. 6 shows a lateral sectional view of a sealing station 17 for a skin pack 1. The base 3 is stored in the second, lower frame 25. The first frame 23 is lowered onto the second frame 25, whereby part of the base 3 and the top film 7 are clamped in between to form a gas-tight sealing tool chamber 45. An optional sealing plate 41 is shown inside the first frame 23, which is in an upper position and can be moved to push a sealing surface 43 of the sealing plate 41 downwards to form a sealing seam 44. An edge support 47 serves as a counter element for forming the desired pressure. The top film 7 is still straight, with an inner section 49 of the top film 7 and an inner section 50 of the base 3 being inside, and outer sections 51 of the top film 7 and outer sections 52 of the base 3 being outside the closed sealing tool chamber 45. Parts of the outer sections 51, 52 are clamped between the first and second frames 23, 25. Through channels 53 within the frames 23, 25, water can be directed to cool the frames 23, 25.

In the following, the function of the sealing station 17 for manufacturing a skin pack 1 is described in more detail using the figures. The base 3 is provided in a sealing tool lower part 21 with a product 5 placed on the base 3 and then a top film 7, which is a skin film, is fed above product 5 and base 3. Then the sealing tool chamber 45 is closed by pressing together the first frame 23 of the sealing tool upper part 19 and the second frame 25 of the sealing tool lower part 21, whereby the top film 7 and the base 3 are clamped circumferentially between the first and second frames 23, 25 and the sealing tool chamber 45 is gas-tightly closed by pressing together. Thus inner sections 49, 50 of top film 7 and base 3 are inside the sealing tool chamber 45 and outer sections 51, 52 are outside the sealing tool chamber 45.

The inner section 49 of the top film 7 is now sucked into the dome 35 of the sealing tool upper part 19 by forming a vacuum in the region between dome 35 and top film 7. There the inner section 49 of the top film is heated.

When the sealing tool chamber 45 is closed, the top film 7 is clamped with the base 3 in the edge region 11 of the skin pack 1 outside a sealing region 9 between the first frame 23 of the sealing tool upper part 19 and the second frame 25 of the sealing tool lower part 21, so that this edge region 11 of the top film 7 and the base 3 is neither deformed by a pressure difference nor heated and thus no sealing of the top film 7 with the base 3 takes place in this edge region 11.

A vacuum is then created in the space between the top film 7 and the base 3. By creating the atmospheric pressure between dome 35 or sealing tool upper part 19 and top film 7, the top film 7 lies on the base 3 and the product 5 positioned thereon.

In a common variant, the base 3 is provided in the form of a tray with a product 5 inserted into the tray.

Preferably, a sealing plate 41 is pressed down on an edge support 47 of the sealing tool lower part 21 and the top film 7 and base 3 located on it, thus forming a sealing seam 44.

Air is usually evacuated and supplied above the top film 7 via air channels 37 in the dome 35 of the sealing tool upper part 19.

Based on the above shown embodiments of a skin pack 1 and a sealing station 17, many variations of the same are possible. For example, the sealing station 17 can be configured to seal more than two rows of skin packs 1 at the same time. If flat bases 3 are used, they may also have ribbing or other embossing, which increases the stiffness of the base 3. In addition to the variants shown here, the offset 13 can also have any other shape which is suitable for spacing the base 3 from the top film 7.

From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting.

The constructions and methods described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention.

As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow. 

What is claimed is:
 1. A skin pack comprising: a base and a top film; wherein the top film is a skin film; wherein the base and the top film are sealed together in a gas-tight manner along a circumferential sealing region; and wherein the base and the top film extend in one or more edge regions disposed outside the sealing region, wherein the base and the top film and are not sealed together in the one or more edge regions.
 2. The skin pack according to claim 1, wherein the sealing region comprises a sealing seam.
 3. The skin pack according to claim 1, wherein the base in the edge region has an offset, and wherein the top film spans over the offset in order to facilitate gripping of the top film and opening of the skin pack by pulling off the top film.
 4. The skin pack according to claim 1, wherein the base is a tray that is a thermoformed bottom film.
 5. The skin pack according to claim 1, wherein the circumferential sealing region has a discrete angulation adjacent to the tear-open corner.
 6. A method for manufacturing a skin pack, the method comprising the steps of: providing a base in a sealing tool lower part; placing a product on the base; feeding a top film above the product and the base, wherein the top film is a skin film; pressing together a first frame of a sealing tool upper part and a second frame of a sealing tool lower part to close a sealing tool chamber, wherein the sealing tool chamber is closed gas-tightly; clamping the top film and the base circumferentially between the first and second frames wherein an inner section of the top film and an inner section of the base are disposed inside the sealing tool chamber and an outer section of the top film and an outer section of the base are disposed outside the sealing tool chamber; sucking the inner section of the top film into a dome of the sealing tool upper part by forming a vacuum in a region between the dome and the top film; heating the inner section of the top film; forming a vacuum in a space between the top film and the base; establishing an atmospheric pressure between one of the dome or the sealing tool upper part and the top film to move the top film such that it lies on the base and the product positioned thereon; and clamping the top film and the base in an edge region of the skin pack outside a sealing region between the first frame of the sealing tool upper part and the second frame of the sealing tool lower part when the sealing tool chamber is closed, so that this edge region of the top film and the base is neither deformed by a pressure difference nor an application of heat so that the top film and the base are not sealed together in the edge region of the skin pack outside the sealing region.
 7. The method according to claim 6, wherein the base is a tray and the product is placed into the tray.
 8. The method according to claim 6, further comprising the step of pressing down a sealing plate on an edge support of the sealing tool lower part and the top film and base located thereon to form a sealing seam.
 9. The method according to claim 6, wherein the sucking the inner section of the top film into a dome of the sealing tool upper part step and the establishing an atmospheric pressure between the dome or the sealing tool upper part and the top film step occurs through one or more air channels in the dome of the sealing tool upper part.
 10. A sealing station for manufacturing a skin pack, the sealing station comprising: a sealing tool upper part with a first frame and a concave dome comprising one or more air channels; a sealing tool lower part with a second frame and a base holder; wherein at least one of the sealing tool upper part and the sealing tool lower part is height-adjustably mounted to be brought closer to each other and to contact each other on their first and second frames and to thereby form a gas-tight sealing tool chamber; and wherein the sealing station is operable to connect a base to a top film in a gas-tight manner by forming a sealing region, wherein the top film is a skin film; and wherein the first frame of the sealing tool upper part and the second frame of the sealing tool lower part clamp a section of the base and a section of the top film so that they are excluded from heating and deformation during the sealing process.
 11. The sealing station according to claim 10, further comprising a height-adjustable sealing plate, the sealing plate comprising a sealing surface which is suitable for connecting a base to a top film in a gas-tight manner by forming a sealing seam.
 12. The sealing station according to claim 10, wherein at least one of the first frame of the sealing tool upper part and the second frame of the sealing tool lower part is formed at least in sections from one of a plastic or a ceramic material.
 13. The sealing station according to claim 10, wherein at least one of the first frame of the sealing tool upper part and the second frame of the sealing tool lower part is cooled by water-cooling channels running in the at least one of the first frame of the sealing tool upper part and the second frame of the sealing tool lower part.
 14. The sealing station according to claim 10, wherein the second frame of the sealing tool lower part has a recess that accommodates an offset of the base in order not to deform the offset when the base and the top film are clamped between the first frame and the second frame.
 15. The sealing station according to claim 10, wherein the sealing tool lower part is at least partially replaceable in order to receive one of a plurality of bases, wherein each of the plurality of bases has a different shape, and wherein at least one of the plurality of bases has a tray shape. 